Method for connecting a catheter balloon with a catheter shaft of a balloon catheter

ABSTRACT

A method for connecting a catheter balloon with a catheter shaft of a balloon catheter that improves the welding quality of a weld between the catheter balloon and the catheter shaft of the balloon catheter. Preferably, a welding energy absorbing device is arranged, preferably in the form of a coloured tubing, in the area of a fixation site after attaching a pre-fixation and then to irradiate this welding energy absorbing device with the radiation energy to carry out the welding. After the welding the pre-fixation and the welding energy absorbing device are removed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a method for connecting a catheterballoon with a catheter shaft of a balloon catheter.

2. Background Information

In a known method this connection is carried out by local welding, forexample by means of laser welding. This local welding requires locatingthe light beam on the connection site. In order to do so, for carryingout the known method the machine has to be adjusted exactly or thewelding site has to be positioned exactly, respectively. However, thisadjustment is very complicated, prone to errors and often requiresmanual correction of the apparatus. In addition to that, laser weldinginvolves the problem that the total technical effort is very high andthat examinations carried out in the context of the invention have shownthat poor uniformity of the weld is often the result. In addition tothat, in this method the material must be adapted to the radiationsource.

In view of the above, it will be apparent to those skilled in the artfrom this disclosure that there exists a need for an improved method forconnecting a catheter balloon with a catheter shaft of a ballooncatheter. This invention addresses this need in the art as well as otherneeds, which will become apparent to those skilled in the art from thisdisclosure.

SUMMARY OF THE INVENTION

It is thus the object of the present invention to provide a method forconnecting a catheter balloon with a catheter shaft of a ballooncatheter the technical effort of which is lower and the welding resultsof which are improved compared to prior art.

The foregoing object can basically be attained by performing a methodcomprising the following steps: arranging a catheter balloon on acatheter shaft; attaching a pre-fixation for temporary fastening of theballoon to a desired fixation site of the catheter shaft; arranging awelding energy absorbing device in the area of the fixation site of thecatheter balloon on the catheter shaft; irradiating the welding energyabsorbing device with radiation energy; and removing the pre-fixationand the welding energy absorbing device after welding the balloon withthe catheter shaft.

One advantage of the method according to the invention is that anydesired materials can be used for the catheter balloon and the cathetershaft or catheter tube, respectively, since an adaptation to theradiation source to be used can be carried out by the welding energyabsorbing device. During assembly the welding energy absorbing devicedefines the exact position at which welding is carried out afterwards orenergy is injected, respectively. Consequently, no complex machineadjustment has to be carried out, since the required localization of thelight beam is achieved by this external welding energy absorbing devicewhich can be arranged exactly in the area of the desired weld in thearea of the fixation site. A higher degree of automation of the weldingapparatus is thus possible, involving at the same time higher accuracyand thus higher quality of the weld.

In addition to this, a distinction can be made between energy injectionand fixation or sealing, respectively, of the welding site in the givenarrangement, which makes an intensive flow of material possible. Adisplacement of material during the welding process and/or an intensivemixture of material are thus possible.

Furthermore, another advantage is that the method according to theinvention is independent of the energy source, so that a variety ofdifferent radiation sources can be used.

As a particularly simple pre-fixation a heat shrink tubing can be used,which is applied to the pre-fixation site and is capable of fixing andsealing the fastening portion to be welded with the catheter shaft.

There are also several embodiments of welding energy absorbing devicespossible. A particularly simple embodiment is a coloured tubing whichcan be applied via the pre-fixation exactly to the site at which thewelding between balloon catheter and catheter shaft is to be carriedout. In a further embodiment the pre-fixation is already locallycoloured and thus serves both as pre-fixation and welding energyabsorbing device. In addition to this, a coloured marking on thepre-fixation, for example a marking with a felt-tip pencil (Edding), canserve as welding energy absorbing device.

An alternative is a stiletto which can be inserted into the cathetershaft. On the stiletto a coloured area can be attached which can bepositioned exactly at the site where the welding is desired. In thiscase, the welding is carried out “from within”.

As has been explained above, a variety of different radiation sourcesare possible, such as laser sources, monochromatic or polychromaticlight sources or other electromagnetic radiation sources. In thiscontext it is important to bear in mind that the welding substrate andthe focussing device have to differ in their absorption behaviour to ahigh degree.

These and other objects, features, aspects and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses preferred embodiments of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a schematically considerably simplified representation of aballoon catheter to explain a first embodiment of the inventive method,and

FIG. 2 is a representation of the balloon catheter corresponding to FIG.1 to explain a second embodiment of the inventive method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments of the present invention will now be explained withreference to the drawings. It will be apparent to those skilled in theart from this disclosure that the following descriptions of theembodiments of the present invention are provided for illustration onlyand not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

Referring to FIGS. 1 and 2, a proximal area of a balloon catheter 3 isillustrated in accordance with a first embodiment of the presentinvention. In this area a catheter balloon 1 is to be fastened on acatheter shaft 2 at two fixation sites V or V′, respectively, viafastening portions 8 or 8′, respectively. In order to explain theinventive method reference is made below to the schematicallyconsiderably simplified representation of the area of the fixation siteV, the principles of which may also be used at the site V′.

In FIG. 1, an embodiment of the inventive method is shown, in which apre-fixation 4, in this case in the form of a heat shrink tubing, isapplied at the beginning, which fastens/connects the fastening portion 8on the desired area of the catheter shaft 2. In the embodiment shown inFIG. 1, a coloured tubing 5 is then applied to the pre-fixation 4, whichconstitutes a welding energy absorbing device whose absorption isadapted to the light source whose course of beam is symbolised by thewavy arrow L.

After arrangement of the pre-fixation 4 and tubing 5, the fixation siteV is irradiated with homogenous radiation. This results in welding ofthe fastening portion 8 of the catheter balloon 1 with the desiredportion of the catheter tubing 2.

The advantage of this method is that the assembly of the welding energyabsorbing device already defines the localization of the welding site.The welding is carried out in an automated manner in a homogenouslyexcited area without precise requirements with regard to the position ofweld metal. In doing so, the irradiated area can also be considerablylarger than the welding site itself.

After the welding has been carried out both the welding energy absorbingdevice and the pre-fixation 4 are removed.

In FIG. 2, an alternative embodiment is shown in which in the area ofthe fixation site V a stiletto 6 having a coloured area 7 is insertedinto the catheter shaft 2 on the distal side for welding with thefastening portion 9 of the catheter tubing 1 or with the fasteningportion 9′, respectively. In this embodiment the stiletto 6 and thecoloured area 7 form the welding energy absorbing device 5′.

After pre-fixation, for example by means of a heat shrink tubing 4according to the embodiment of FIG. 1, another irradiation with the helpof the radiation source L can be carried out, so that the weldingexplained above in connection with the method according to FIG. 1 byinjection of the radiation energy is achieved exactly in the area of thedesired site of connection.

It should also be noted that the weld metal or the light source has tobe turned during the welding process or the light source has to bering-shaped. The pre-fixation or the heat shrink tubing, respectively,also serves as welding protection tube to ensure an even distribution ofheat.

As has been explained above, a variety of different radiation sourcesare possible, such as laser sources, monochromatic or polychromaticlight sources or other electromagnetic radiation sources. In thiscontext it is important to bear in mind that the welding substrate andthe focussing device have to differ in their absorption behaviour to ahigh degree.

The terms of degree such as “substantially”, “about” and “approximately”as used herein mean a reasonable amount of deviation of the modifiedterm such that the end result is not significantly changed. These termsshould be construed as including a deviation of at least ±5% of themodified term if this deviation would not negate the meaning of the wordit modifies.

This application is based on European Patent Application No.02029113.4-2310 filed on Dec. 31, 2002, and published on Jul. 7, 2004.The entire disclosure of European Patent Application No. 02029113.4-2310is hereby incorporated herein by reference.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

1-19. (canceled)
 20. A method comprising the following steps: attachinga pre-fixation device for temporary fastening of a balloon to a desiredfixation site of a catheter shaft; arranging a welding energy absorbingdevice separate from the pre-fixation device in the area of the fixationsite of the catheter balloon on the catheter shaft; irradiating thewelding energy absorbing device with radiation energy; and removing thepre-fixation device and the welding energy absorbing device afterwelding the balloon with the catheter shaft.
 21. The method according toclaim 20, wherein the pre-fixation device comprises a colored area. 22.The method according to claim 20, wherein the attaching of thepre-fixation device includes a heat shrink tubing being applied on thefixation site.
 23. The method according to claim 20, wherein the weldingenergy absorbing device includes a colored area.
 24. The methodaccording to claim 20, wherein the arranging of the welding energyabsorbing device includes a colored tubing being applied on thepre-fixation device.
 25. The method according to claim 20, whereinarranging a welding energy absorbing device comprises positioning astiletto having a colored area into the catheter shaft in the area ofthe desired fixation site as the welding energy absorbing device. 26.The method according to claim 20, wherein the irradiating of the weldingenergy absorbing device with radiation energy includes using one of alaser light, a monochromatic light or a polychromatic light as a lightsource or using an electromagnetic radiation source.
 27. The methodaccording to claim 20, wherein the radiation energy has an at leastalmost homogeneous distribution.